施氮量和花后土壤含水量对强筋小麦籽粒淀粉合成及品质的影响

Effects of Nitrogen Fertilizer Rate and Post-anthesis Soil Moisture Content on Starch Synthesis and Quality of Grains in Strong Gluten Wheat

以强筋小麦品种济麦20为材料,在防雨池栽培条件下研究了施氮量和花后土壤含水量对强筋小麦籽粒淀粉合成及其品质的影响,以明确强筋小麦获得高产优质的花后适宜土壤含水量及施氮量.结果表明：在同一施氮量下,适宜的花后土壤含水量（60%～70%）籽粒游离态淀粉合成酶（SSS）和束缚态淀粉合成酶（GBSS）活性在籽粒发育过程中一直最高,有利于直链淀粉、支链淀粉的积累和支链淀粉/直链淀粉比的提高,提高峰值粘度、低谷粘度、最终粘度和衰减值;花后土壤含水量过高（80%～90%）或过低（40%～50%）均导致籽粒SSS和GBSS活性降低,从而使直链淀粉、支链淀粉的积累量降低,减小支链淀粉/直链淀粉比,使峰值粘度、低谷粘度、最终粘度降低.（2）在同一土壤含水量下,增施氮肥不利于灌浆前期SSS和GBSS活性和直链淀粉、支链淀粉积累量的提高,并且随着土壤含水量增加增施氮肥该趋势加重;适量增施氮肥能提高支链淀粉/直链淀粉比和峰值粘度、低谷粘度、最终粘度,过多或过少施氮则降低支/直比和峰值粘度、低谷粘度、最终粘度.研究认为,在本试验条件下,适量增施氮肥（纯氮225 kg/hm2）或适宜的花后土壤含水量（60%～70%）可促进强筋小麦籽粒淀粉的合成,有效改善其淀粉品质.

The study was intended to discuss suitable soil moisture content after anthesis and nitrogen fertilizer rate for high yield and good quality of strong gluten wheat ‘Jimai 20＇. Effects of nitrogen fertilizer rate and post-anthesis soil moisture content on starch synthesis and quality of grains in strong gluten wheat was tested under proof-rainfall pool culture condition. Under the same level of nitrogen fertilizer rate with suitable soil moisture content （60%-70%） after anthesis, the activity of soluble starch synthase （SSS） and granule-bound starch synthase （GBSS） remained the highest during grain development in wheat. Meanwhile,it enhanced aecumulation of amylose and amylopectin, and improved amylopectin to ＂amylase ratio, peak viscosity,trough viscosity, final viscosity and break down. However, under the same level of nitrogen fertilizer rate with over high soil moisture content （80%-90%） and low soil moisture content （40%-50%） ,it resulted in decreasing the activity of SSS and GBSS, and reducing accumulation of amylose and amylopectin,amylopectin to amylase ratio, peak viscosity, trough viscosity, final viscosity. Under the same level of soil moisture content during early grain filling stage,increased nitrogen fertilization was not favor to the improvement of the activity of SSS and GBSS and the accumulation of amylose and amylopectin. Moreover, with the increase of soil moisture content, increased nitrogen fertilization aggravate the tendency. Properly increased nitrogen fertilization can improve amylopectin to amylase ratio, peak viscosity, trough viscosity, final viscosity, but overabundance or shortage nitrogen fertilization can decrease them. It is coneluded that properly increased nitrogen fertilization or suitable soil moisture content after anthesis can promote starch synthesis and improve starch quality in wheat grains.